Systems capable of monitoring the areas around a vehicle are already known in the automotive sector, particularly the so-called “omnivision” systems, which offer a 360° view around the vehicle itself. An overview of several systems known in patent literature is offered below.
At present, so-called AVM (acronym for “Around View Monitor”) systems are widely used. These systems are based on a plurality of cameras installed in different positions on the vehicle and oriented downwards. The cameras supply an image made up of: a first portion, concerning an area to the front of the vehicle according to a view from above and a second portion, concerning an area to the rear of the vehicle and the areas at the sides of the vehicle, according to a view from above.
The image is projected on a display inside the vehicle for the purpose of providing driving support to a driver. In particular, the image is displayed differently based on a type of driving. For example, if the vehicle is proceeding forward, the area in front is displayed in a wider view, whereas if the vehicle is proceeding in reverse the area in the rear is given priority.
An example of an AVM system is proposed in document US 2014/0036063. The main limitation of the example AVM system relates to the fact that it takes a top-view shot of the surroundings of the vehicle, so that objects extending from the ground are distorted when projected in the image on the display. In other words, while objects that are level with the ground, that is, substantially flat, are correctly detected and projected on the display (hypothesis on the removal of perspective), the detection of objects outcropping (or raising) from the ground is not reliable.
In the automotive field, there is an ever-increasing demand for active driving support systems that are capable of reliably monitoring the surroundings of a vehicle for the purpose of detecting and reporting dynamic events (e.g., possible collisions) to the driver so as to assist him/her in making decisions regarding subsequent maneuvers. “Situation awareness” is an expression used in the automotive field precisely to define the perception of elements present in the environment in a volume defined in terms of space and time, an understanding of the meaning of such elements, and the projection of the state thereof in the immediate future. Active driving support systems employ diverse components for the purpose of offering a 360° view of the surroundings of the vehicle, such as cameras located on board the vehicle in various positions, and active sensors such as radar, lidar laser scanners, ultrasonic sensors, etc.
Document U.S. Pat. No. 8,044,781 discloses and claims a system and a method for displaying the surroundings of a vehicle three-dimensionally according to a viewpoint that can be changed based on the driving situation. The system comprises the use of sensor devices capable of measuring the distances of objects present around the vehicle.
The document refers to sensors of various types, such as stereo pairs, radar sensors, lidar sensors, time-of-flight sensors, etc., whose fields of view are partially overlapping. In one embodiment, the sensors are mounted on the rear and on both sides of the vehicle. The sensors communicate with a processor, which, based on the distances detected, generates a three-dimensional reconstruction of the surrounding environment. The three-dimensional reconstruction is presented in the form of a map on a display and is continuously updated, with a viewpoint that is adaptable to the particular driving situation. Based on recognition of the objects and the driving situation, the processor decides which elements to highlight on the three-dimensional map.
Document U.S. Pat. No. 6,151,539 discloses an autonomous vehicle arrangement capable of planning a route in response to receiving travel orders (e.g., point of origin and destination point) as input. The arrangement comprises: at least one range sensor located in the front area of the vehicle, at least one range sensor located in the rear area of the vehicle, a plurality of ultrasonic and/or microwave radar sensors located on the sides of the vehicle, and two cameras, one located in the front area and one in the rear area of the vehicle. However, the arrangement proposed in U.S. Pat. No. 6,151,539 does not provide a 360° view of the surroundings the vehicle.
Document US 2013/0033604 concerns a camera to be installed on each of the rear-viewing side mirror units for use in a so-called “all-around view” system. The system comprises a plurality of cameras mounted on the vehicle to capture a respective number of images, which, suitably combined, make it possible to reconstruct an overall bird's-eye image of the surroundings of the vehicle. The main drawback of the camera proposed in US 2013/0033604 relates to the fact that as the camera is mounted on a rear-viewing side mirror, it is unable to cover the entire area to the side of the vehicle horizontally.
Document US 2013/0329005 also refers to an all-around view system comprising a plurality of cameras and a processing unit that reconstructs a top view of the surroundings of a vehicle. Like all systems that provide a view from above (also known as a “bird's-eye view”), the main disadvantage lies in the distortion of the objects that extend from the ground.
Omnivision systems of the prior art are based on the use of a plurality of monocular cameras or stereoscopic pairs, or they make use of an omnidirectional camera. Moreover, there are also omnivision systems that are based on a plurality of laser scanning sensors that provide partially overlapping fields of view so as to give continuity to the image obtained. This obviously involves the disadvantage of computational complexity, given that the overlapping areas must be processed to eliminate undesired duplication of data. In addition to the drawbacks relating to top views, the all-around view systems of the prior art that employ a plurality of cameras are not capable of providing a complete 360° view of the surroundings of a vehicle. The all-around view in conventional systems leave several blind spots, which can prove to be of critical importance during maneuvers at low speeds such as parking, entering driveways, entering garages, etc.
The all-around view systems based on the use of an omnidirectional camera installed on the vehicle to provide a 360° panoramic view instead suffer from other limitations. The first of such limitations is a low resolution of the camera due to the amplitude of the field of view (view over 360°). Furthermore, to offer a 360° view, the camera is equipped with hyperbolic mirrors, thereby creating a cumbersome arrangement vulnerable to deterioration from the environment and/or to damage. Lastly, the all-around view systems of the prior art are equipped with a display for viewing the surroundings of a vehicle and obstacles and their distance from the vehicle may be highlighted on the display. However, a mere view of the scene is offered to the driver.